Application of SNP molecular marker combination in identifying material property excellent plant of liriodendron chinense, primer pair combination and kit

Abstract

The application discloses a kind of SNP molecular marker combination in identifying the application of material superior plant of Liriodendron chinense, primer pair combination and kit, belong to biological breeding technical field.The application discloses SNP molecular marker for identifying the material superior plant of Liriodendron chinense, which is composed of 6 SNP molecular markers, and each SNP molecular marker corresponds to one SNP site.Based on the result of resequencing, 6 pairs of SNP primers are developed, as shown in SEQ ID NO.1-12, and multiple primer combinations can be used to identify candidate material superior plant and its source source, and can also be used to construct the fingerprint code of material superior plant of Liriodendron chinense, which can distinguish material superior plant and non-superior plant at molecular level.The method has the advantages of high accuracy, good stability, simple operation, etc., and can play a positive role in molecular marker assisted breeding and variety protection of Liriodendron chinense.

Description

Technical Field

[0001] This invention relates to the application of SNP molecular marker combinations in identifying superior Liriodendron tulipifera timber varieties, primer pair combinations, and kits, belonging to the field of biobreeding technology. Background Technology

[0002] Liriodendron chinense (Hemsl.) Sarg. is a precious native broad-leaved tree species in subtropical China and is listed as a national second-class protected rare and endangered plant. With its straight trunk, excellent wood quality, and beautiful flowers and leaves, it possesses value for timber, ornamental purposes, and ecological purposes, making it an excellent timber and carbon sink species. Compared with traditional coniferous timber species such as Masson pine, Liriodendron chinense wood has a higher cellulose content, lower lignin content, and lower extractive content, which is beneficial for pulp and paper making, demonstrating unique industrial application potential.

[0003] However, despite the numerous advantages and selection potential of Liriodendron tulipifera, its genetic improvement efforts still face key technological bottlenecks. Traditional selection of superior plants relies primarily on field phenotypic observation, a method that is not only time-consuming and costly but also easily affected by environmental factors, leading to low selection accuracy and efficiency. More critically, the genetic background of important wood properties such as basic density and fiber length in Liriodendron tulipifera is complex, and the relevant molecular identification technology system is still underdeveloped, significantly limiting the efficient identification and early selection of superior germplasm.

[0004] Therefore, there is an urgent need to develop molecular markers that can accurately and rapidly identify superior plantlets in terms of wood properties. Compared to traditional markers such as SSRs, SNPs are widely distributed and densely distributed in the genome, making them more suitable for high-throughput, automated, and precise identification. However, most SNPs are located in intergenic regions and are mostly neutral variations, resulting in limited genotyping stability and application reliability. SNPs in gene functional regions have more defined genomic locations and higher detection stability, making them suitable as molecular identification markers for superior plantlets in terms of wood properties. This can improve the efficiency of identifying superior germplasm, reduce the cost of phenotypic identification, provide technical support for the early identification, germplasm management, and intellectual property protection of individuals with superior wood properties, and lay the foundation for subsequent genetic analysis and gene mapping research.

[0005] To address the aforementioned technical problems, this invention develops a set of specific SNP marker combinations from functional gene regions based on genome resequencing technology. These combinations are primarily used for the molecular identification and precise identification of superior Liriodendron tulipifera seedlings, providing a new method for their early, rapid, and stable identification, thereby accelerating the breeding process. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, the primary technical problem this application aims to solve is to provide an application of SNP molecular marker combinations in identifying superior Liriodendron tulipifera (Christmas lily) timber. Another technical problem this application aims to solve is to provide primer pairs and kits for detecting the aforementioned SNP molecular marker combinations.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] Application of a SNP molecular marker combination in identifying superior Liriodendron tulipifera (Liriodendron chinense) timber quality, wherein the SNP molecular marker combination consists of 6 SNP loci, and the locations and base types of the 6 SNP loci on the Liriodendron chinense reference genome are as follows:

[0009] SNP1: Located at position 17144448 on chromosome LchiChr5 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A;

[0010] SNP2: Located at position 45520208 on chromosome LchiChr5 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being C and base type 2 being G;

[0011] SNP3: Located at position 4424349 on chromosome LchiChr10 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A;

[0012] SNP4: Located at position 21365222 on chromosome LchiChr14 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A;

[0013] SNP5: Located at position 40904215 on chromosome LchiChr15 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A;

[0014] SNP6: Located at position 4340185 on chromosome LchiChr18 in the Liriodendron tulipifera genome of NCBI version GCA_984586915.1, with base type 1 being C and base type 2 being A.

[0015] A primer pair combination for detecting SNP molecular marker combinations in the application, comprising the primer pairs shown in SEQ ID NO. 1 and SEQ ID NO. 2 for detecting SNP1, the primer pairs shown in SEQ ID NO. 3 and SEQ ID NO. 4 for detecting SNP2, the primer pairs shown in SEQ ID NO. 5 and SEQ ID NO. 6 for detecting SNP3, the primer pairs shown in SEQ ID NO. 7 and SEQ ID NO. 8 for detecting SNP4, the primer pairs shown in SEQ ID NO. 9 and SEQ ID NO. 10 for detecting SNP5, and the primer pairs shown in SEQ ID NO. 11 and SEQ ID NO. 12 for detecting SNP6.

[0016] The application of the primer pair combination in identifying superior Liriodendron tulipifera timber plants includes the following steps:

[0017] 1) Extract DNA from the Liriodendron tulipifera sample to be tested, and perform PCR amplification using the primer pair combination to obtain amplification products of SNP1~6 sites.

[0018] 2) Sequencing the amplification products of SNPs 1-6, and then confirming the base types of SNPs 1-6 based on the sequencing results:

[0019] SNP1 site: The amplification product is 492bp in length, base type 1 is G, base type 2 is A, and the SNP is located at 347bp in the amplification product.

[0020] SNP2 site: The amplification product is 465bp in length, base type 1 is C, base type 2 is G, and the SNP is located at 267bp in the amplification product.

[0021] SNP3 site: The amplification product is 401bp long, the base type 1 is G, the base type 2 is A, and the position of SNP in the amplification product is 282bp.

[0022] SNP4 site: The amplification product is 414bp long, the base type 1 is G, the base type 2 is A, and the SNP is located at 157bp in the amplification product.

[0023] SNP5 site: The amplification product is 314bp in length, base type 1 is G, base type 2 is A, and the SNP is located at 210bp in the amplification product.

[0024] SNP6 site: The amplification product is 610bp in length, base type 1 is C, base type 2 is A, and the SNP is located at 455bp in the amplification product.

[0025] 3) The base types of SNP1~6 sites are sequentially converted into fingerprint codes of the Liriodendron tulipifera samples to be tested. Wherein, 0 indicates that all base types of the SNP site are 1, 1 indicates that two base types coexist, and 2 indicates that all base types are 2.

[0026] 4) Compare the fingerprint code of the Liriodendron tulipifera sample to be tested with the fingerprint code of the standard superior plant species. The fingerprint code of the standard superior plant species is as follows:

[0027] Superior strain name: Ⅱ-8-1, fingerprint code: 100000;

[0028] Superior strain name: Ⅱ-10-1, fingerprint code: 200000;

[0029] Superior strain name: Ⅱ-15-1, fingerprint code: 000011;

[0030] Superior strain name: Ⅰ-20-3, fingerprint code: 000010;

[0031] Superior strain name: Ⅱ-29-3, fingerprint code: 200010;

[0032] Superior strain name: Ⅱ-30-1, fingerprint code: 200110;

[0033] Superior strain name: Ⅰ-147-1, fingerprint code: 000001;

[0034] Superior strain name: Ⅰ-148-1, fingerprint code: 002000;

[0035] Superior strain name: Ⅰ-149-1, fingerprint code: 000000;

[0036] Superior strain name: Ⅰ-151-1, fingerprint code: 001000;

[0037] Superior strain name: Ⅰ-154-8, fingerprint code: 020000;

[0038] Superior strain name: Ⅱ-204-2, fingerprint code: 220202;

[0039] If the fingerprint code of the tested Liriodendron tulipifera sample matches any of the standard superior plant fingerprint codes, then it is a superior Liriodendron tulipifera plant; otherwise, it is not.

[0040] The application of the primer pair combination in the preparation of a kit for identifying superior Liriodendron tulipifera timber species.

[0041] A kit for identifying superior Liriodendron tulipifera timber plants, comprising the aforementioned primer pair combination.

[0042] The kit also includes DNA extraction reagents.

[0043] The kit also includes PCR amplification reagents and / or sequencing reagents.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] The SNP molecular markers disclosed in this invention for identifying superior Liriodendron tulipifera timber species consist of 6 SNP molecular markers, each corresponding to a SNP site. These SNP sites are all derived from the exon regions of genes, and their sequences are relatively stable, making them ideal regions for fingerprinting.

[0046] Because the genome of Liriodendron tulipifera contains a large number of non-coding regions, accounting for more than 90% of the genome, unlike previous methods that used random SNP or SSR sequences from the whole genome for fingerprint code construction and molecular marker identification, the SNP markers screened in this invention are all derived from the exon regions of genes, resulting in more stable and reliable sequencing and identification results.

[0047] Based on the results of high-throughput resequencing, this invention developed six pairs of SNP primers. Multiple primer combinations can be used to identify candidate superior trees with excellent timber characteristics and to construct a timber fingerprint code for *Liriodendron tulipifera*. At the molecular level, this method can differentiate and identify the germplasm and individual superior trees of *Liriodendron tulipifera*. This method has the advantages of high accuracy, good stability, and simple operation, which improves the success rate of identifying superior trees with excellent timber characteristics and plays a positive role in molecular marker-assisted breeding and variety protection of *Liriodendron tulipifera*. Attached Figure Description

[0048] Figure 1 Fingerprint patterns of 12 superior Liriodendron tulipifera trees. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to specific embodiments. Unless otherwise described in detail, the technical means used in the following embodiments are all conventional means well known to those skilled in the art.

[0050] This application used 7-year-old tulip trees from 39 families across 12 provenances as materials. A completely randomized block design experiment was conducted to analyze the genetic variation of their wood properties. The study found that basic wood density had the greatest heritability, and based on this, 12 families with superior wood properties were selected. Furthermore, considering growth, plant type, adaptability, and other indicators, 12 superior plants were selected from these 12 superior families (Table 1). All of these superior plants were planted at the Dongfanghong Reservoir base in Leping City, Jiangxi Province, with an average basic density of 0.52 g / cm³. 3 It is significantly greater than the average density of 0.48 g / cm³. 3 .

[0051] Table 1. Information on the 12 superior Liriodendron tulipifera trees with excellent timber properties and their sources in this application.

[0052]

[0053] Two to three fresh, tender leaves were collected from each of the 12 superior Liriodendron tulipifera mother trees, placed in sealed bags containing silica gel for drying, and then stored at -80°C. All sample information is summarized in Table 1.

[0054] Example 1

[0055] 1. DNA extraction

[0056] The extraction of genomic DNA from Liriodendron tulipifera was performed using a novel plant genomic DNA extraction kit. The specific steps were as follows:

[0057] Take approximately 20 mg of Liriodendron tulipifera leaves, flash-freeze in liquid nitrogen, and grind into a fine powder. Add 400 μL of Buffer LP1 and 6 μL of LNase A (10 mg / mL), vortex for 1 min, and let stand at room temperature for 10 min. Add 130 μL of Buffer LP2, vortex for 1 min, centrifuge at 12000 rpm for 5 min, and transfer the supernatant to a new centrifuge tube. Add 1.5 times the volume of Buffer LP3 and mix thoroughly. Add all the solution and precipitate obtained in the previous step to the adsorption column already loaded into the collection tube. If the solution cannot be added all at once, it can be added in multiple batches. Centrifuge at 12000 rpm for 1 min, discard the waste liquid in the collection tube, and put the adsorption column back into the collection tube. Add 500 μL of Buffer GW2 to the adsorption column, centrifuge at 12000 rpm for 1 min, discard the waste liquid, and put the adsorption column back into the collection tube. Repeat this step twice. Centrifuge at 12000 rpm for 2 min, discard the waste liquid in the collection tube, and allow the adsorption column to air dry completely at room temperature for several minutes. Transfer the adsorption column to a new centrifuge tube, add 50-100 μL of Buffer GE or sterile water dropwise to the center of the adsorption membrane, incubate at room temperature for 2-5 min, centrifuge at 12000 rpm for 1 min, and collect the DNA solution. Store the DNA at -20℃.

[0058] 2. Development of polymorphic sites

[0059] The extracted DNA from all samples was homogenized to maintain a concentration of 150-200 ng / μL for each sample. After passing the initial testing, all 12 samples were resequencing with 10× coverage using the BGI Genomics next-generation sequencing platform. After sequence quality control, the data were aligned to the *Liriodendron chinense* genome (version GCA_984586915.1) on the NCBI database (https: / / www.ncbi.nlm.nih.gov / datasets / genome / ?taxon=3413) to obtain all SNP variant sites for all samples.

[0060] 3. Construction of fingerprint codes for superior Liriodendron tulipifera timber

[0061] Based on the results of the variant identification, in order to ensure the accuracy of the identification results, polymorphic SNP sites with a genotype deletion rate of 0 were selected from the gene exon regions of the Liriodendron chinense genome. After optimization, six variant sites with high diversity were finally selected (Table 2).

[0062] Table 2. Information on 6 SNP sites in Liriodendron tulipifera

[0063]

[0064] Note: In this application, the gene code follows the following naming rules: "Lchi" represents Liriodendron chinense (Hemsl.) Sarg.; "Chr" represents chromosome, and the number to the right of "Chr" represents chromosome number; "G" represents gene, and the number to the right of "G" represents gene number on that chromosome; the number to the right of "." represents gene version.

[0065] The fingerprint codes of 12 superior Liriodendron tulipifera specimens were constructed using the base information of these 6 SNP polymorphic sites (Table 3).

[0066] Table 3 Fingerprint codes of 12 superior Liriodendron tulipifera trees.

[0067]

[0068] Where 0 indicates that all SNP sites are of base type 1, 1 indicates that two base types coexist, and 2 indicates that all SNP sites are of base type 2.

[0069] Different colors were assigned to different base types at the six SNP sites for each sample to visualize the fingerprint code and form a fingerprint map. The results are as follows: Figure 1As shown, the 12 superior strains can be clearly distinguished by six SNP loci. For example, II-204-2 can be distinguished from other samples by both SNP6 and SNP4; superior strains I-151-1 and I-148-1 can be identified from all other samples by SNP3; II-8-1 and II-30-1 can be distinguished from other samples by SNP1 and SNP4, respectively. Furthermore, using SNP5 and SNP6 together can directly identify superior strains II-15-1 and I-147-1; using SNP2 and SNP6 together can identify superior strain I-154-8; and adding SNP1 and SNP4 can identify II-10-1, I-20-3, II-29-3, and I-149-1 from all other samples.

[0070] Ultimately, a combination of six SNP molecular markers was determined to be able to distinguish superior strains of Liriodendron tulipifera with different wood properties, which were used to construct the DNA fingerprint code of Liriodendron tulipifera.

[0071] Example 2

[0072] 1. Design and synthesis of SNP site primers

[0073] Primers were designed using Primer-BLAST from the NCBI website. Each primer pair was required to be at least 50 bp away from the polymorphic site, and the product length was set between 200 bp and 800 bp. A total of 6 pairs of SNP primers were designed (Table 4) and synthesized by Sangon Biotech (Shanghai) Co., Ltd.

[0074] Table 4. Amplification primers for 6 pairs of SNP sites

[0075]

[0076] 2. Screening of SNP primers and product detection for identifying superior Liriodendron tulipifera timber varieties

[0077] Using the genomic DNA of 12 superior Liriodendron tulipifera plants as templates, PCR amplification was performed using the 6 pairs of SNP primers in Table 4 to obtain PCR amplification products.

[0078] PCR reaction system (20μL): 10μL of 2× Bio Taq PCR Mix (+Dye) Mix solution, 40ng of DNA template, 0.2μM each of forward and reverse primers, and ddH2O to bring the total to 20μL.

[0079] Touch Down PCR reaction program: 95℃ pre-denaturation for 5 min; 95℃ denaturation for 30 s, 65-55℃ annealing (decreasing by 0.7℃ per cycle) for 30 s, 72℃ extension for 40 s, 15 cycles; 95℃ denaturation for 30 s, 55℃ annealing for 30 s, 72℃ extension for 40 s, 20 cycles; 72℃ extension for 4 min.

[0080] PCR products were detected using a 1.2% agarose gel electrophoresis at 120V for 15-20 minutes. Primer amplification showed clear bands, and the fragment size matched the target fragment size.

[0081] The PCR product containing the target fragment was amplified and sent to Sangon Biotech (Shanghai) Co., Ltd., where the amplification primer products were used for sequencing.

[0082] Sequencing revealed that the sequencing results of all 6 SNP sites were consistent with the initial resequencing results. The lengths of the SNP site amplification products and the polymorphic site bases are shown in Table 5.

[0083] Table 5 Information on 6 SNP sites

[0084]

[0085] Example 3:

[0086] Twelve superior plants from six germplasm sources (Table 6) were selected for leaf collection and DNA extraction. PCR amplification was performed using the six primer pairs in Table 4 of Example 2.

[0087] Table 6 Information on 12 superior wood-bearing plants

[0088]

[0089] PCR reaction system (20μL): 10μL of 2× Bio Taq PCR Mix (+Dye) Mix solution, 40ng of DNA template, 0.2μM each of forward and reverse primers, and ddH2O to bring the total to 20μL.

[0090] Touch Down PCR reaction program: 95℃ pre-denaturation for 5 min; 95℃ denaturation for 30 s, annealing at 65-55℃ (decreasing by 0.7℃ per cycle) for 30 s, extension at 72℃ for 40 s, 15 cycles; 95℃ denaturation for 30 s, 55℃ annealing for 30 s, extension at 72℃ for 40 s, 20 cycles; 72℃ extension for 4 min. PCR amplification products were sent to Sangon Biotech (Shanghai) Co., Ltd. for first-generation sequencing using the amplification primer sequences.

[0091] Based on the sequencing results, the base information at 6 SNP sites was obtained from 12 Liriodendron tulipifera samples, and converted into fingerprint codes. The results are shown in Table 7. The identification results are consistent with the actual seed source of the samples, with an identification accuracy of 100%.

[0092] Table 7. Amplified fingerprints and provenance identification results of 12 superior Liriodendron tulipifera specimens.

[0093]

[0094] Example 4

[0095] Twenty-one tulip tree samples were randomly selected, including 12 superior specimens and 9 non-superior specimens, numbered Sample 1 to Sample 21. Genomic DNA was extracted from each sample. Sequence amplification was performed using six pairs of SNP primers. The sample DNA extraction, amplification, and sequencing methods were the same as in Example 3.

[0096] Based on the base sequencing results of different samples at 6 SNP sites, fingerprint codes were generated for identification and verification. The specific identification results are shown in Table 8. Twelve superior strains could be identified based on their amplified fingerprints at the 6 SNP sites, while the amplified fingerprints of the nine non-superior strains differed from these 12 superior strains. For example, all 12 superior strains only had two types (0 and 2) at the SNP2 site; therefore, any sample with a type (1) could be identified as a non-superior strain. Furthermore, other non-superior strains could be identified by combining their fingerprints with those of other SNP sites.

[0097] Table 8. Identification results of 21 samples of Liriodendron tulipifera

[0098]

[0099] The above description is illustrative only and not restrictive of the present invention. Those skilled in the art will understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined by the appended claims, and all such modifications, variations or equivalents will fall within the protection scope of the present invention.

Claims

1. The application of a combination of SNP molecular markers in identifying superior Liriodendron tulipifera timber plants, characterized in that, The SNP molecular marker combination consists of 6 SNP sites, and the locations and base types of the 6 SNP sites on the Liriodendron tulipifera reference genome are as follows: SNP1: Located at position 17144448 on chromosome LchiChr5 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A; SNP2: Located at position 45520208 on chromosome LchiChr5 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being C and base type 2 being G; SNP3: Located at position 4424349 on chromosome LchiChr10 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A; SNP4: Located at position 21365222 on chromosome LchiChr14 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A; SNP5: Located at position 40904215 on chromosome LchiChr15 in the Liriodendron tulipifera genome of NCBI version number GCA_984586915.1, with base type 1 being G and base type 2 being A; SNP6: Located at position 4340185 on chromosome LchiChr18 in the Liriodendron tulipifera genome of NCBI version GCA_984586915.1, with base type 1 being C and base type 2 being A.

2. A primer pair combination for detecting SNP molecular marker combinations in the application of claim 1, characterized in that, It includes the primer pairs shown in SEQ ID NO. 1 and SEQ ID NO. 2 for detecting SNP1, the primer pairs shown in SEQ ID NO. 3 and SEQ ID NO. 4 for detecting SNP2, the primer pairs shown in SEQ ID NO. 5 and SEQ ID NO. 6 for detecting SNP3, the primer pairs shown in SEQ ID NO. 7 and SEQ ID NO. 8 for detecting SNP4, the primer pairs shown in SEQ ID NO. 9 and SEQ ID NO. 10 for detecting SNP5, and the primer pairs shown in SEQ ID NO. 11 and SEQ ID NO. 12 for detecting SNP6.

3. The application of the primer pair combination according to claim 2 in identifying superior Liriodendron tulipifera timber plants, characterized in that, The application includes the following steps: 1) Extract DNA from the Liriodendron tulipifera sample to be tested, and perform PCR amplification using the primer pair combination described in claim 2 to obtain amplification products of SNP1~6 sites. 2) Sequencing the amplification products of SNPs 1-6, and then confirming the base types of SNPs 1-6 based on the sequencing results: SNP1 site: The amplification product is 492bp in length, base type 1 is G, base type 2 is A, and the SNP is located at 347bp in the amplification product. SNP2 site: The amplification product is 465bp in length, base type 1 is C, base type 2 is G, and the SNP is located at 267bp in the amplification product. SNP3 site: The amplification product is 401bp long, the base type 1 is G, the base type 2 is A, and the position of SNP in the amplification product is 282bp. SNP4 site: The amplification product is 414bp long, the base type 1 is G, the base type 2 is A, and the SNP is located at 157bp in the amplification product. SNP5 site: The amplification product is 314bp in length, base type 1 is G, base type 2 is A, and the SNP is located at 210bp in the amplification product. SNP6 site: The amplification product is 610bp in length, base type 1 is C, base type 2 is A, and the SNP is located at 455bp in the amplification product. 3) The base types of SNP1~6 sites are sequentially converted into fingerprint codes of the Liriodendron tulipifera samples to be tested. Wherein, 0 indicates that all base types of the SNP site are 1, 1 indicates that two base types coexist, and 2 indicates that all base types are 2. 4) Compare the fingerprint code of the Liriodendron tulipifera sample to be tested with the fingerprint code of the standard superior plant species. The fingerprint code of the standard superior plant species is as follows: Superior strain name: Ⅱ-8-1, fingerprint code: 100000; Superior strain name: Ⅱ-10-1, fingerprint code: 200000; Superior strain name: Ⅱ-15-1, fingerprint code: 000011; Superior strain name: Ⅰ-20-3, fingerprint code: 000010; Superior strain name: Ⅱ-29-3, fingerprint code: 200010; Superior strain name: Ⅱ-30-1, fingerprint code: 200110; Superior strain name: Ⅰ-147-1, fingerprint code: 000001; Superior strain name: Ⅰ-148-1, fingerprint code: 002000; Superior strain name: Ⅰ-149-1, fingerprint code: 000000; Superior strain name: Ⅰ-151-1, fingerprint code: 001000; Superior strain name: Ⅰ-154-8, fingerprint code: 020000; Superior strain name: Ⅱ-204-2, fingerprint code: 220202; If the fingerprint code of the tested Liriodendron tulipifera sample matches any of the standard superior plant fingerprint codes, then it is a superior Liriodendron tulipifera plant; otherwise, it is not.

4. The use of the primer pair combination according to claim 2 in the preparation of a kit for identifying superior Liriodendron tulipifera timber species.

5. A kit for identifying superior Liriodendron tulipifera timber plants, characterized in that, It includes the primer pair combination as described in claim 2.

6. The reagent kit according to claim 5, characterized in that, It also contains DNA extraction reagents.

7. The reagent kit according to claim 5, characterized in that, It also includes PCR amplification reagents and / or sequencing reagents.

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